The range request header allows requesting only part of a resource (like a limited set of bytes of a static file).

The system can be used when serving static files, but it is disabled by default. Just add –honour-range to enable it.

In the future it will be used for file wrappers (like wsgi.file_wrapper) and for The GridFS plugin (this is the reason for not enabling it by default
as you could have already implemented range management in your app)